Our JH600s' stalling problem is probably a multi-faceted problem. In my case, clearly the decompression valve and cam had something to do with its stalling a few month ago. Since those are mechanical parts, subject to constant wear and tear, they'd deteriorate as mileage builds up. The fact that it failed to function normally only after around 10km indicated an inherent design problem nonetheless.

Another possible cause for stalling has just been discovered. It is reported on a Chinese JH600 forum today that the connection mechanism from the ECU module to the circuit board is not reliably designed and easily damaged. The consequence of its failure is again sporadic stalling.

The original report can be found here.

The ECU connects to the circuit board through 2 "spring contacts" in the following picture:


As the bike moves about the springs eventually would become weak or lose adequate contact pressure. One fellow JH600 rider had experienced idential stalling problem as ours, which recovered its previous "as new" condition after he rewired the contact points as follows:


This particular cause of stalling has nothing to do with the ECU programming. It is just a bad mechanical/electrical design.

I will have mine checked (by Dr. Cui) to see if it is part of the stalling problem on my Jialing.